Undesirable noise and vibration produced during operation of an automotive vehicle is commonly quantified as a noise, vibration, and harshness (“NVH”) rating. Automotive brakes are a common source of NVH. Specifically, the interaction between friction materials on a brake pad with a brake rotor causes the brake pad and brake rotor to vibrate, which can not only result in brake squeal, but also brake shuddering and other effects.
Various techniques have been used to attenuate the NVH of automotive brakes. Different friction materials, and the way that friction materials are shaped onto a brake pad can affect the NVH produced during operation. These techniques alone, however, are generally insufficient to reduce NVH to an acceptable level.
Another common technique for attenuating the NVH produced by a brake system is to include a damping element with the brake pad to damp the vibration caused by the interaction between the friction material of the brake pad and the brake rotor. In one example, a shim is affixed to the back side of a brake pad. A shim generally includes layers of different materials such as, for example metal, rubber, and fibrous materials. The layers are arranged in a stacked structure configured to damp vibration of the brake pad.
Damping elements, such as the examples described above, are generally susceptible to the harsh service conditions of automotive brakes. For instance, a damping element may migrate out of position, corrode, lose adherence to the brake pad or experience delamination. These issues can lead to a decrease in the damping provided by the damping element. Protecting a damping element from migration generally requires additional adhesive material or additional structural features on the back side of the brake pad. Protecting a damping element from corrosion generally requires additional protective material. These protection techniques, however, generally require additional machining or assembly of the brake pad, and may not be adaptable to some shapes and sizes of brake pads.
Therefore, a damping element for a brake pad that resists corrosion would be beneficial. A damping element that does not require additional adhesive material or structural features on the brake pad to resist migration would also be beneficial. A damping element that can be applied to a wide variety of sizes and shapes of brake pads would also be beneficial.